MCM 2-10 V2

Question 1

2 major tissue types

Answer 1

cellular - composed mainly of cells, integritys/properties derived from cell junctions

connective - composed mainly of ECM with few blasts that synthesize, model, bind ECM. physical properties based on ECM organization (LCT, cartilage, bone, tendon)

Question 2

anchoring/adhering junctions

Answer 2

primary purpose is to maintain tissue integrity when subjected to mechanical stress. can be cell:cell or Cell:Ecm

Question 3

three major components of all anchoring/adhering junctions

Answer 3

1. transmembrane glycoprotein - anchoring portion
2. linker proteins on cytosolic face - regulates assembly and connects to cytoplasm
3. cytoskeleton - connection to IF or micro (actin) filaments. distributes force due to mech stress over large area, prevents glycoprotein detatchment

Question 4

Four types of anchoring junctions and what they connect

Answer 4

adherens junctions/zonula adherens - Cell:cell anchoring junctions

Focal adhesions/conctacts - Cell:ECM

Desmosomes: Cell:cell

Hemidesmosomes: Cell:ECM

Question 5

What are the Cell:Cell and what are the common features?

What are the Cell:ECM and common features?

Answer 5

Cell:Cell - adherens and desmosomes.

• cadherin glycoprotein
• homophilic

Cell:ECM = focal adhesions, hemidesmosomes

• integrin
• heterophilic

Question 6

adherens junctions

Glycoprotein?
Hetero/Homo?
Cytoskeleton made of?
Interaction type?
Purpose?

Answer 6

cadherin
homo
actin
cell:cell
provide strength, important in development

Question 7

focal adhesions

Glycoprotein?
Hetero/Homo?
Cytoskeleton made of?
Interaction type?
Purpose?

Answer 7

integrin
hetero
actin
Cell:ECM
Orient contractions, important in development

Question 8

Desmosomes

Glycoprotein?
Hetero/Homo?
Cytoskeleton made of?
Interaction type?
Purpose?

Answer 8

Caderin
Hemo
IF
Cell:cell
Maintain tissue integrity

Question 9

Hemidesmosomes

Glycoprotein?
Hetero/Homo?
Cytoskeleton made of?
Interaction type?
Purpose?

Answer 9

integrin
hetero
IF
Cell:ECM
maintain tissue integrity

Question 10

Tight Junctions

Provide?
Major proteins?
Hetero/Homo?

Answer 10

1. provide permeability layer across epithelial sheets allowing for regulated transport of nutrients through cells. ALSO maintains cell polarity keeping membrane transport proteins in correct locations
2. claudin/occludin
3. homophilic

-cytoskeleton not needed for integrity of tight junctions

Question 11

Gap Junctions

Provide?
Major proteins?
Regulated by?

Answer 11

provide means of communication between neighboring cells, passage of small molecules.
-single proteins called connexin, 6 connexin form connexon. 1 connexon from each cell forms gap junctions.

regulated by Calcium and pH
high Ca/Low pH = close, cLOWse
low Ca/High pH = open